The invention relates to a preparation method of an
antibacterial peptide cecropin feed additive, belonging to the technical field of
gene engineering. The preparation method of the
antibacterial peptide cecropin feed additive comprises the following steps of: (1) carrying out
enzyme cutting to an
antibacterial peptide cecropin gene and a multicopy integration
expression vector respectively by Not I, after connecting by
DNA ligase, converting E.coli TOP10 bacterial strains,
coating an LB (Luria-Bertani) flat plate, carrying out
enzyme cutting verification by the Not I, and selecting and naming a transformant inversely inserted into a cecA1 fragment as pYIP-cecA1; (2) carrying out
enzyme cutting to the pYIP-cecA1 prepared in step (1) by using Hpa I, recovering big fragments, adding the pYIP-cecA1 into 80 muL of
yeast electricity transformation competent cells, carrying out
electric shock on a mixture, and screening the mixture by the YEPD (
Yeast Extract Peptone Dex) flat plate of G418 to obtain the
yeast cell for expressing the cecropin; and (3) culturing the
yeast cell for expressing the cecropin, which is prepared in step (2), and
drying to obtain the cecropin
feed additive. According to the preparation method, the production cost of the cecropin can be lowered, and a good foundation is laid for popularizing the cecropin to serve as the feed additive to be
antibiotics substitute for feeds.